The high desert here sits at 1,500 metres, so winters are cold (snow common from December to February) and summers are hot but dry (daytime highs over 35°C in July and August). Spring and autumn are the most pleasant, with cool nights and warm days.
The first weekend of October — the Northern Navajo Nation Fair — is the best time to visit if you want to see something happening. Otherwise come in late spring (May) or autumn (September, October) when the light is at its best on the rock and the air is clear enough to see for fifty miles.